This invention pertains to mobile refractory apparatus for repairing interior furnace walls. More particularly, the invention concerns refractory gunning apparatus for spraying fluent refractory slurry mixes to patch cracks and spalls in interior refractory walls of high temperature industrial ovens and furnaces to prevent loss of gas and heat therefrom. The invention is particulary useful in repairing the interior refractory walls of coke ovens while the ovens are maintained at their conventional operating temperatures.
The repair of cracked and spalled interior refractory surfaces of industrial ovens and furnaces, while maintaining such devices at their elevated operating temperatures, long has presented unique problems defying solution. Coke ovens, for example, extend up to 40 feet in length, the entire interiors of which are maintained at approximately 2000.degree. F. Because of their size and high temperatures, it is impractical to repair such ovens adequately with manual labor and equipment. Various refractory gunning machines have been designed for repairing interior refractory walls under high temperature conditions, but such machines have achieved only limited degrees of success. Examples of such devices are illustrated by U.S. pat. Nos. 3,473,737, 3,827,633 and 3,957,203. Such known refractory gunning machines lack the broad range of maneuverability to adequately service most coke ovens, and none of them are capable of repairing the innermost areas of such ovens. Such devices, also, when thrust into the high temperature atmospheres of industrial ovens and furnaces have a tendency to overheat and possibly break down because of inadequate cooling systems.